Metastatic pheochromocytomas and paragangliomas: where are we?

Pheochromocytomas and paragangliomas (PPGLs) can metastasize in approximately 15–20% of cases. This review discusses the available evidence on the biology and treatment of metastatic PPGLs. Chemotherapy is the first-line treatment option for this evolving and symptomatic disease. In patients with high MIBG uptake and positive PETGa-68, radiometabolic treatment may be considered. The efficacy of sunitinib has been shown in observational studies, and pembrolizumab has been evaluated in phase II clinical studies, while other agents investigated in this setting are anti-angiogenic drugs cabozantinib, dovitinib, axitinib and lenvatinib. As these agents' efficacy and safety data, alone or in combination, are scant and based on few treated patients, enrollment in clinical trials is mandatory. Future therapeutic options may be represented by DNA repair system inhibitors (such as olaparib), HIF2 inhibitors and immunotherapy.